Change speed mechanism



May 17, 1932. w. w. EDWARDS 1,858,389

CHANGE SPEED MECHANI SM Filed June 1. 193.1

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Patented May 17, 1932 reach WILLIAM W. EDWARDS, OF LOS ANGELES,CALIFORNIA CHANGE SPEED MECHANISM Continuation of application. SerialNo. 413,243, filed December 11, 1929. This application filed June 1,

1931. Serial This invention relates to a change-speed mechanism and moreparticularly pertains to a variable-speed drive for drill presses; thisapplication being a continuation of an application filed December 11,1929, Serial Number 413,243.

An object of the invention is to provide a change-speed transmissionmechanism whereby a wide range of different speeds may be is imparted toa driven member from a prime mover, in which manually operable means areprovided for effecting change of the driving speed so formed andarranged as to permit ready selection of the various changes of itspeed.

Another object is to provide a selective change-speed mechanismembodying a multiplicity of change-speed transmission elements with amanual control of few parts which are easily operated and are not liableto get out of order. v

Another object is to provide a change-speed transmission mechanismincluding a countershaft, a driven shaft and a series of powertransmitting sprocket wheels on the countershaft connected by sprocketchains to companion sprocket wheels on the driven shaft in whichmanually operable key means are provided whereby any one set of thesprocket wheels may be selectively operatively connected to th shaftsindependent of the other sets of sprocket wheels and whereby rotation ofthe drive shaft will effect rotation of only one set of the sprocketwheels at a time while the remaining sets of sprocket wheels remainstationary thus effecting an economy in power consumption, and obviatingall possibility of the transmission becoming jammed.

Another object is to provide a construction in a transmission mechanismof the above character whereby key connection between the wheels and theshafts may be readily effected irrespective of variation in the relativepositions of the Wheels of the several sets thereof. so as to obviateany necessity of power driving of the counter-shaft in order to bringabout such connection.

A further object is to provide a means for placing the counter-shaft outof operative connection with a source of power which is manuallyoperable to turn the counter-shaft in effecting key connection betweenthe counter shaft and any of the transmission wheels thereon.

With the foregoing objects in View, together with such other objects andadvantages as may subsequently appear, the invention resides in theparts and in the combination, construction and arrangement of partshereinafter described and claimed and illustrated by way of example inthe accompanying drawings, in which:

Figure 1 is a view of the change-speed mechanism as seen in frontelevation with parts broken away;

F igure'2 is a View of the change-speed mechanism as seen in sideelevation with portions removed and illustrating parts thereof invertical section on the line 2-2 of Figure 1;

Figure 3 is a detail in cross section as seen on the line 3-3 of Figure2;

Figure 4 is a view in section and elevation as seen on the line 4.4c ofFigure 2;

Figure 5 is a detail in cross section taken on the line 5-5 of Figure 2;

Figure 6 is a detail in longitudinal section of a fragmentary portion ofthe countershaft showing the key connection in a neutral position.

Referring to the drawings more specifically, A indicates the standard ofa drill press which is fitted with a cap B, and on which is mounted forvertical slidable movementa sleeve C carrying a frame D on which ismounted a change-speed mechanism and a source of power for operating adrilling mechanism; the sleeve C being raised and lowered on thestandard A through the medium of a vertical screw E threaded in the capB and adapted to be driven by mechanism (not shown) on the frame D.

The source of power carried-on the frame D comprises a two-speedelectric motor F, preferably a and cycle motor operable at speeds ofeither 1000 R. P. M. or 1200 R. P. M. The motor F has the usual driveshaft 10 on which is fixedly mounted a pair of corresponding sprocketpinions 11 and 12. A counter-shaft G is revolubly mounted in bearings 13and 14 carried by the frame D and the sleeve 0 respectively, which shaftis arranged on a plane above the drive shaft 10 and extends in parallelrelation thereto, and loosely mounted on the outer end portion of thecounter-shaft G is a pair of sprocket wheels 15 and 16 disposed inalignment with the pinions 11 and 12 respectively; the wheels 15 and 16being of different diameters. A sprocket chain 17 passes around andengages the pinion 11 and wheel 15 and a sprocket chain 18 passes aroundand engages the pinion 12 and wheel gear 16.

Means are provided for effecting interconnection between either of thewheels 15 and 16 and the counter-shaft G, which means embodies anannular slide H encompassin the outer end portion of the counter-shaftand slidable longitudinally thereon, and also includes a bar 19 arrangedin a longitudinal channel 20 formed in the counter-shaft G. The outerend portion of the counter-shaft G projects beyond the bearing 13 andhas afiixed to its end a knob 21 between which and the bearing 13 theslide H is mounted, which knob serves as a hand hold for effectingmanual rotation of the counter-shaft.

The channel 20 extends lengthwise of the counter-shaft G from a pointadjacent the knob 21 to a point beyond the portion of the counter-shaftencircled by the hubs of the wheels 15 and 16, which hubs are formedwith keyways 22 and 23 of a width corresponding to the width of thechannel 20 and adapted to be aligned therewith. The bar 19 is formed atits inner end with an upward projection constituting a key 24 which isadapted to be positioned in engagement with either the keyway 22 orkeyway 23 of the wheels 15 and 16. The outer end of the bar 19 is formedwith a lug 25 which is normally engaged in a channel 26 formedinteriorly of the slide H; the slide being formed of a pair of annularplates 27 and 28 which are secured together by screws 29 and on adjacentfaces of which are formed recesses to constitute the channel 26. Theslide H is thus constructed to permit ready formation of the channel 26and to facilitate its assemblage on the counter-shaft in engagement withthe lug 25.

Interposed between the bar 19 and the bottom of the channel 20 is abowed plate spring 30 the ends of which are seated on the bottom of thechannel and the intermediate portion of which bears against theunderside of the bar 19 and is affixed to the latter as by rivet ing.The spring 30 acts to normally maintain the bar 19 in an outermostposition with the key 24 engaged with either the keyway 22 or 23 andwith the lug 25 engaging the channel 26 on the slide H. The spring 30,however, is adapted to be depressed to permit retraction of the key 24into the channel 20 as will be later described.

Extending parallel to the counter-shaft G is a driven shaft I which isdisposed on a plane below the counter-shaft G; the driven shaft beingsupported at its outer end on a bearing 33 carried by the frame I) andhas its inner end portion mounted in suitable bearings, not shown. Thedriven shaft I consti tutes a drill impeller and accordingly has itsinner end suitably connected in driving relation to a drill in aconventional manner by means not necessary to be here shown.

Loosely mounted on the countershaft G is a series of sprocket wheels J,K, L and M; the wheels J K and L being preferably of correspondingdiameters while the wheel M is of a larger diameter. Loosely mounted onthe driven shaft I is a series of sprocket wheels N, O, P and Q,arranged in alignment with the wheels J, K, L and M respectively whichwheels N, O, P and Q, are of decreasing diameters in the orderspecified. Sprocket chains J, S, T and U pass around and engagerespectively the wheels J and N, K and O, L and P and M and Q. Means areprovided for selectively interconnecting either of the sets of wheels J,K, L, M, N, O, P and Q, with the counter-shaft G and the driven shaft Iwhereby the latter may be rotated at various speeds from and relativelyto the counter-shaft G. This means is here shown as embodying a slide V,particularly shown in Figure 3, which is carried on the counter-shaft Gand driven shaft I and is mounted to slide longitudinally thereon. Theslide V comprises a pair of sleeves a and b which are slidably mountedon the countershaft G and the driven shaft I respectively, and areconnected together by tie-bars c and d.

Aflixed to the slide V intermediate the ends thereof is a bar W whichextends parallel with the shafts G and I through a guide hearing 40 andhas its outer end projecting forward of the frame D fitted with a knob41'. The bar W is formed with a series of spaced sockets 42 and mountedin the bearing 40 is a spring-pressed detent 44 adapted to be engagedwith either of the sockets 42 to hold the bar W against longitudinalmovement in any one of several longitudinally adjusted positions.

The shafts G and I are formed with longitudinally extending channels 35and 35 rc spectively which extend along the portions of the shaftsencompassed by the hubs of the wheels thereon and along portions of theshafts extending forward of the wheels, and mounted in the channels 35and 35 are bars 36 and 36 adapted to be shifted longitudinally of thechannels; the outer ends of the 4 bars 36 and 36 being formed with lugs37 and 37 which project into annular channels 6 and f formed interiorlyof the sleeves a and Z) of the slide V whereby on moving the latter thebars 36 and 36 will be moved therewith.

The hubs of the wheels J K, L, M, N, O, P and Q are formed with keywaysj, is, Z, m, a, o, p and q-respectively, which correspond in width toand are adapted to be aligned with the channels 26 on the shafts G andI, and the inner ends of the bars 36 and 36 are formed with keys 38 and38 which are adapted to be positioned in engagement with the keyways;the key 38 on the bar 36 carried by the counter-shaft G being adapted tobe engaged with any one of the keyways j, 76, Z and m, and the key 38 onthe bar 36 carried by the driven shaft I being adapted to be engagedwith any one of the keyways n, 0, p and g. The keys 38 and 38 are spacedequi-distant from the sleeves a and b so as to lie on a common planewhereby they are disposed to be engaged with the opposed pairs ofwheels, or to be positioned neutrally inter mediate the adjacent pairsof wheels.

Spring 39 and 39 are arranged to bear between the under sides of thebars 36 and 36 and the bottoms of the channels 35 and 35 and act tonormally maintain the bars 36 and 36 in their outermost positions sothat the keys 38 and 38 thereon may be engaged with the keyways underpressure of the springs 39 and 39, yet permit recession of the bars 36and 36 into the channels when necessary to retract the keys thereon intothe channels.

In the operation of the invention, setting the motor F in operationeffects rotation of the shaft 10, the pinions 11 and 12, the

sprocket chains 17 and 18, and the wheels 15 and 16, and rotation of thecounter-shaft G will be effected either from the wheel 15 or the wheel16 according to whether the key 24 on the bar 19 is disposed inengagement with the keyway 22 on the wheel 15 or the keyway 23 on thewheel 16. The countershaft G may thus be driven at either of fourspeeds, two of which are controlled by the wheel 15 and the two speedsof the motor and the other two of which are controlled by the wheel 16and the two speeds of the motor; the counter-shaft being driven at slowspeed by connecting the wheel 15 therewith and operating the motor atits low speed, and being driven at a faster speed by operating the motorat its high speed while the wheel 15 is in operative connection with thecounter-shaft. The countershaft is rotated at its highest speed byoperatively connecting the wheel 16 therewith and operating the motor atits high speed, and may be operated at its third speed by operating themotor at slow speed while the wheel 16 is operatively connected to thecounter shaft. Operation of the motor at its two speeds is governed bythe usual switch and V the two-speed construction of the motor, not

necessary to be here shown as the same is well known in the art. Toeffect operatlve connection of either the wheel 15 or 16 with thecounter-shaft G the slide H is manually shifted longitudinally of thecounter-shaft thereby causing the bar 19 to advance therewith and movethe key 24 either into engagement with the wheel 15 or the wheel 16 asthe case may be.

It will be understood that by reason of the difference in diameters ofthe wheels 15 and 16, the keyways 22 and 23 therein will seldom if everbe disposed in accurate alignment with each other, so that the ends ofthe keyways at'the contiguous faces of the wheel hubs will be closed bywall portions of the adjacent hubs, and accordingly when the bar 19 isshifted to move the key 24 thereon out of engagement with one of thekeyways the key will be engaged by the adjacent hub and will bedepressed into the channel. so as to then be held out of engagement witheither of the keyways first by one hub then by the other when the key isdisposed intermediate the wheels. It follows that by moving the slide Hto an intermediate position the key 24 will be disposed in a neutral.position so that rotation of the wheels 15 and 16 will not betransmitted to the counter-shaft and the latter will then remain at restuntil the key is moved to a position clear of one of the hubs and withinthe boundaries of the other so that on rotation of the latter the keythereon will pe moved to a position to be engaged by the Key.

It will now be seen that as the wheels 15 and 16 are loose on thecounter-shaft G and are driven continuously fromthe motor, the freewheel may be disposed with its keyway out of register with the channel20 in the counter-shaft, and that in this event, in shifting the bar 19from one of its wheelengaging positions to the other the key 24 will, onadvancing against the end of the hub of either of the wheels, bedepressed by reason of the end faces of the key being inclined and alsoby reason of the bar 19 being movable inwardly. The key 24 may thus bedisposed between the ends of the hub of the wheel while, out ofalignment with the keyway therein, and if the wheels are revolvingduring this operation the key will then ride into engagement with thekeyway. In event shifting of the key is effected while the wheels 15 and16 are stationary the key may be moved into engagement with the keywayby manually turning the countershaft through the medium of the knob 21.

This permits of the interconnection between cither of the wheels 15 and16 and the counter-shaft being made while the power drive is off so asto obviate the impact on the key connection which would occur incffecting speed change while the motor is in operation.

In like manner the keys 38 and 38 on the bars 36 and 36 are cooperablewith the keyways and hubs of the wheels on the shaft G and I onreciprocation of the bars 36 and 36' that is when the slide V isdisposed to position the keys 38 and 38 at an intermediate position tobe overlapped by the end portions of the hubs of contiguous wheels, asshown in Figure 6, ti keys will be held out of operative relation to thewheels so that the counter-shaft may then be rotated without effectingrotation of any of the transmission wheels J, K, L and M andconsequently these wheels together with their encompanying chains andthe companion wheels on the driven shaft will then be stationary.

lVhen it is desired to effect connection between the counter-shaft andany one of the wheels J, K, L and M thereon, the slide V is shifted,while the counter-shaft is stationary, to dispose the key 38 in aposition between the ends of the hub of the selected wheel J, K, L, orM, whereupon the countershaft is manually turned by the knob 21 to bringthe key 38 opposite the keyway in the selected wheel whereupon the keywill be caused to enter the keyway under the urge of the spring 39.Movement of the slide V will at the same time effect positioning of thekey 38 between the ends of the hub of the wheel N, O, P, or Q pairedwith the selected wheel J, K, L, or M, so that on rotation of thecounter-shaft as above described, which will effect rotation of theselected wheel, its encompassing chain and its companion wheel, the key38 will be caused to engage the keyway of such companion wheel under theurge of the spring 39.

On impelling the counter-shaft the driven shaft I will be rotated at aspeed according to which of the wheels N, O, P and Q, is operativelyconnected therewith which, in turn, is determined by the position of thekey 38 on the bar 86 which is, in turn, determined by the position ofthe slide V andits connected bar IV; the latter being disposed in adesired position by the operator shifting it longitudinally in thebearing 40.

The series of sockets 42 in the outer end portions of the bar WV servesto indicate to the operator the particular wheels J, K, L, lVI, N, O, Por Q engaged by the keys 38*38; the sockets 42 being spaced apart oncenters distances corresponding to the spacing of the longitudinalcenters of the wheels on the shafts G and I and being arrangedrelatively thereto and to the detent 44 that when the latter is engaged,for example, with the outer socket 42, as shown in Figure 2, the keys 38and 38 will be in operative engagement with the wheels M and Q and byadvancing thebar IV to dispose the other sockets 42 in engagment withthe detent- 44, the keys 38 and 38 will be advanced successively intooperative relation with the wheels LP, K-S, and JN. The keys 38 and 38have their end faces inclined and the bars 36 and 36' may be depressedinto the channels 35 and 35' in order to permit the key to move intoposition between the ends of the hubs of the several wheels in event thekeyways thereon are disposed out of alignment with the channels 35 and35 in the manner previously described with reference to the key 24.

The shaft I will be rotated at a speed which will vary according towhich of the wheels N, 0,1 and Q is operatively connected therewith; thewheels N, O, P and Q, being of progressively decreasing diameters. Theshaft I may thus be rotated at four speeds from the counter-shaft G andthe latter being operable at either of four speeds gives a range of 16speeds to the driven shaft I. Obviously the range of the speeds of theshaft I may be increased. by increasing the number of transmissionconnections between the driven shaft and the counter-shaft and betweenthe counter-shaft and the motor-driven shaft.

By the arrangement here shown I have produced a change-speed drivingmechanism for a drill press which, with a motor operable at either 1000or 1200 R. P. Ms a drill driven from the shaft. I may be revolved atspeeds ranging from to 1000 It. P. Ms through the range of sixteen speedchanges.

I claim:

In a change-speed mechanism, a counter-shaft, a driven shaft, a seriesof sets of sprocket wheels loosely revoluble on each of said shafts, asprocket chain interconnecting each set of said wheels, each of saidwheels being formed with akeyway extending longitudinally of andcontiguous the wheel-carrying shafts, the keyways of adjacent wheelsbeing normally disposed out of alignment with each other, a sleeve oneach of said shafts slidable longitudinally thereof, a manually operableslide bar, a connection between said slide bar and each of said sleevesso that reciprocation of said slide bar will effect correspondingmovement of each of said sleeves, a retractable spring-pressed keycarried by each of said shafts slidable longitudinally thereof,connections between said keys and said sleeves for causing said keys tocollectively advance lengthwise of said shafts on eifection movement ofsaid sleeves to dis pose said keys in position to be engaged with thekeyways of companion pairs of said wheels, a knob fixed on saidcounter-shaft manually turnable to rotate said countershaft to disposethe key carried thereby in a position to cause it to be engaged with akeyway on one of the wheels, and means for power driving saidcounter-shaft at variable speeds including manually operable means forplacing said counter shaft in neutral.

' WVILLIAM W. EDWARDS.

